CONICET | Buscador de Institutos y Recursos Humanos

During the last decade global tidal models have spectacularly improved. However, they still have difficulties to resolve tides over continental shelves and near coastlines. Tidal propagation from the continental shelf to the Northpatagonian Gulfs of Argentina is studied applying a set of three nested high resolution models based on the Hamburg Shelf Ocean Model (HamSOM) code, in which particular attention was paid to the bathymetry and the coast line. The study is complemented with the use of all the tidal gauge and tidal currents observations available. Simulations display a good agreement with observations, permitting the construction of higher resolution and more reliable cotidal and corange charts. The tidal regime in the area is essentially semidiurnal and dominated by M2. This constituent propagates northward as a Kelvin wave and reaches the gulfs from the south. In their interior an important amplification is observed. Tidal currents are large at the mouths? of the gulfs, and weaken towards their interior. The non linear transfer of energy from the semidiurnal to higher order harmonics was analyzed. This can be very important in the interior of the gulfs, particularly in Nuevo Gulf and in the northwestern San Matías Gulf, close to San Antonio. Energy flux and energy dissipation by bottom friction has been computed and indicate that this region dissipates 17% of the total energy dissipated on the Patagonian Shelf which, in turn, is one of the most dissipative areas of the world ocean. The Simpson-Hunter parameter computed from the simulations shows that in the mouth of the gulfs, particularly in San Matías and east of the Península de Valdés, the tides are energetic enough to overcome stratification and produce tidal fronts. The locations where tidal fronts are located are highly consistent with results from sea surface temperature and primary productivity data analyzed by other authors.

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